Update 28/04/2014: The short version is, download the update now. Apple approved it in less than eight hours!
Sorry, a bug slipped through into Rootn Tootn 2.0.2. The next reminder will get set to 13 years ago if it’s based on the end of the timer. This only affects duration timers; event timers are unaffected. I have already submitted an update to Apple.
Hopefully it will be approved as quickly as 2.0.2 was, but until then there is a workaround. You can set the reminder to trigger from the start of the duration timer as a temporary workaround. (That is, the opposite of the setting shown on the screenshot to the right).
I apologise again that this got through my testing.